Any news on Tasks in CF Diego?


Andreas Mueller
 

Hi all,

we at SAP are very interested in the new task feature, because we currently run some dummy/fake apps, in order to simulate task-like behavior, which includes some cumbersome app log parsing. The promises of the tasks are exactly what we are looking for, since the starter of the task would just like to see the result of the task action in some convenient and easy to consume way.

Unfortunately we currently know of a number of older and newer resources (URLs) with information on the task topic, which do not give much information on the details of the result handling and seem to even be slightly contradicting in some low level details.

As a starting point, it would be good to know the most recent official documentation on the tasks (for the task implementor and consumer).

To shortly summarize, our most important questions from task implementation and consumption perspective are:

1) How does the task implementation provide its result - either through process exit code and stderr/out or via tracing (+ optional/internal result file)? Is there some definite contract or at least best-practice for the task implementation side?

2) How does the infrastructure collect the task result and especially how is it exposed to the consumer? In the V3 API docu there’s just a result JSON object, with only one “failure_reason” property. We’d also expect the process exit code and maybe stdout/err to be part of the result JSON. Or in case the (optional) ResultFile and callback URL are the way to go, there should be some env var exposed to the task implementation, so that one knows to which file the result data shall be written.

3) It seems like the result from the V3 REST API is not exposed via the V3 tasks client command (at least in its current state)?

4) Is the “Task Completion Callback URL” mechanism that is mentioned in several sources only intended for internal use by client implementations, or also for external consumers?

It would also be interesting, when the tasks will be ready to use.

In the talk on V3 given on European CF Summit (in Sept. in Frankfurt) the following statement on tasks was given ([1] – slides 46/47):
“When? Very soon (~ next few weeks)”

I’ll add some more detailed observations about the potential result handing as a second post.

Thanks a lot and kind regards,
Andreas Mueller – SAP SE

[1] http://schd.ws/hosted_files/cfsummiteu2016/2a/Unleasing%20the%20Power%20of%20the%20V3%20API_Frankfurt.pdf

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